A randomized placebo controlled trial was conducted to examine the effect of DHA on gestational length and cognitive development. 115 pregnant women were supplemented with 300 mg DHA/d or placebo during pregnancy and thru the first 3 mo of breastfeeding (BF).

Bayley Scales of Infant Development (BSID) were administered at 4 mo and 1y. Dietary DHA intake during pregnancy, was 81.9 +/- 5.8 mg/day (95% CI 72.3,91.5) and increased only slightly during BF. Some took prenatal vitamins with 0– 300 mg DHA per day resulting in total DHA intakes of 80 to 1100 mg/day. RBC and plasma phospholipid DHA at entry (expressed as % total fatty acids) were5.94 +/- 1.52 and 5.04 +/- 1.44 (mean +/- SD), respectively. Breastmilk (BM) % total DHA was .53 +/- .037 (mean +/- sem) at 2 mo and decreased to .35 +/- /039 at 4 mo.

BM DHA was significantly greater in the DHA treatment ( p<.02) and with the highest DHA intake compared to the lowest. BM DHA was lowest in carriers of the minor allele of the delta-5 desaturase gene. Data were analyzed by treatment and by DHA intake. DHA supplementation resulted in a 1 wk increase in gestation with a significant (p<.03) 8 d increase in gestational length comparing the highest intake of DHA( > 600 mg/d) to the lowest (< 300 mg/d). BSID cognitive and language scores were 10 points higher with high intake of DHA compared to the lowest (p<.02).

Maternal DHA impacts both pregnancy outcome and subsequent development.